Download Introduction

Intermediate Programming
— Chapter 1 —
MIS 233
Summer 2010
1
Introduction to Computers, the Internet,
and the Web





Introduction
History of Java
Java Class Libraries
Basics of a Typical Java Environment
Thinking About Objects
2
Introduction

Java How to Program, 8th Edition

Java Standard Edition 6 SE 6.0




Mustang
Java 2 Enterprise Edition (J2EE)
Java 2 Micro Edition (J2ME)
J2SE Development Kit (JDK)
3
Introduction

Java How to Program, 8th Edition
 Deitel & Deitel

Java Standard Edition 6 SE 6.0




Mustang
Java 2 Enterprise Edition (J2EE)
Java 2 Micro Edition (J2ME)
J2SE Development Kit (JDK)
4
Introduction


Structured programming
Object oriended programing
5
History of Java

Java
by Sun Microsystems in 1991
team leader: James Gosling
 Originally for intelligent consumer-electronic
devices
 Then used for creating Web pages with
dynamic content

Now also used for:



Develop large-scale enterprise applications
Enhance WWW server functionality
Provide applications for consumer devices (cell
6
Java Class Libraries

Classes
 Contain methods that perform tasks

Return information after task completion
Used to build Java programs
Java contains class libraries
 Known as Java APIs (Application Programming
Interfaces)


7
Basics of a Typical Java Environment

Java systems contain
 Environment
 Language
 APIs
 Class libraries
8
Basics of a Typical Java Environment
(cont.)

Java programs normally undergo five phases
 Edit


Compile


Class loader stores bytecodes in memory
Verify


Compiler creates bytecodes from program
Load


Programmer writes program (and stores program on disk)
Verifier ensures bytecodes do not violate security requirements
Execute

Interpreter translates bytecodes into machine language
9
Basics of a Typical Java Environment
(cont.)

Edit
 extension .java


Integrated development environments IDE



the file contains java source code
writting and editing programs
debuging logic errors
Examples of IDEs:



Eclipse: www.eclipse.org
NetBeans: www.netbeans.org
JBuilder: www.borland.com
10
Basics of a Typical Java Environment
(cont.)

Compile
 source code into bytecodes
 executed by java virtual machine JVM


platform independent instructions



part of the JDK
not dependent on particular hardware platform
portable
Load


class loader takes the .class files and transfers to
mai memory
any class file provided by java into memory as well
11
Basics of a Typical Java Environment
(cont.)

Execute


JVM executes the bytecodes
early versions simply and interpreter


Just-in-time JIT compliation


slower as :one bytecode at a time
combination of interpretation and compilation
Compilation


source to bytecodes (platform independent)
bytecodes to machine language (platform
dependent)
12
Fig. 1.1 A typical Java environment.
Pha se 1
Pha se 2
Edit or
Com piler
Disk
Disk
Prog ram is c reat ed in
the edit or and sto red
on d isk.
Com piler c rea te s
byt ec odes and st ores
the m on disk.
Prim ary
Mem ory
Pha se 3
Class Lo ad er
Class loa de r p ut s
byt ec o des in m em ory.
Disk
.
.
.
.
.
.
Prim ary
Mem ory
Pha se 4
Byt ec ode Ve rifier
.
.
.
.
.
.
Prim ary
Mem ory
Pha se 5
Int erp ret er
.
.
.
.
.
.
By te c ode verif ier
c onf irms t hat a ll
byt ec odes are v alid
and do not violat e
Java ’ s sec urit y
rest ric t ions.
Int erpret er read s
byt ec odes and
translat es them into a
la nguag e t hat t he
c om put er c an
und ersta nd, possib ly
st oring d at a values a s
the program exec ut es.
13
Thinking About Objects

Objects
 Reusable software components that model real-world
items
 Look all around you


Attributes


Size, shape, color, weight, etc.
Behaviors


People, animals, plants, cars, etc.
Babies cry, crawl, sleep, etc.
Examples
 object:student


attributes: name,ID, status,
behavior: takes a course, send to advisor,...
14
Thinking About Objects (cont.)

Examples
 object:bank account



object: employee



attributes: deposited amount, account number
behavior: deposit money, withdraw money , transfer
money,...
attributes:name ,department, salery,...
behavior: make a sale, work in a project, ...
employee...
object: a regtangular shape


attributes:hight, with, x –y coordinate, color,...
behavior:area, cicunference,......
15
Thinking About Objects (cont.)



Object-oriented design (OOD)
 Models real-world objects
class:
 a blueprint for objcets
inheritence:
 new classes of objects are derived absorbing
characteristics of existing classes and adding unique
characteristics of their own
 e.g.:



a manger is a personel
an undergrad student is a student
a saving accout is an bank account
16
Thinking About Objects (cont.)

communication
 Models communication among objects
 send messages to each other
 e.g.:



a bank account object get the message of decreasing the
balance
customer sent the message to withdraw money
encapsulation:

Encapsulates data (attributes) and functions
(behaviors)



Information hiding
Communication through well-defined interfaces
e.g.:

using the breke pedal to stop a car without knowing working
principles
17
Thinking About Objects (cont.)



Object-oriented language
 Programming is called object-oriented programming
(OOP)
 Java, C#
 unit of programming is class
Procedural programming languages
 Programming is action oriented
 C:unit of programming is a function
class:
 from which objects are instantiated (created)
 java classes have


methods: implement opperations
fields: implements attributes
18
Thinking About Objects (cont.)

class:
 classes to objcets
 blueprint to houses
 many objcets can be instantiated from the
same class
 e.g.: a student class

ali, ahmet are particular students
instantiated from the student class
 each has a name, student number
 each can take a corse, pay registation fee,
19
Thinking About Objects (cont.)




Analysis your project requirements
 determining what the system is to do
Design the system
 how the system shold do it
Object-Oriented Analysis and Design (OOAD)
 Essential for large programs
 Analyze program requirements, then develop solution
Unified Modeling Language (UML)
 Graphical language that uses common notation
 Allows developers to represent object-oriented designs
20